On the night of Sept. 11, as the Obama administration scrambled to respond to the Benghazi terror attacks, then-Secretary of State Hillary Clinton and a key aide effectively tried to cut the department’s own counterterrorism bureau out of the chain of reporting and decision-making, according to a “whistle-blower” witness from that bureau who will soon testify to the charge before Congress, Fox News has learned.

That witness is Mark I. Thompson, a former Marine and now the deputy coordinator for operations in the agency’s counterterrorism bureau. Sources tell Fox News Thompson will level the allegation against Clinton during testimony on Wednesday before the House Oversight and Government Reform Committee, chaired by Rep. Darrell Issa, R-Calif.

Fox News has also learned that another official from the counterterrorism bureau — independently of Thompson — voiced the same complaint about Clinton and Under Secretary for Management Patrick Kennedy to trusted national security colleagues back in October.

Thompson considers himself a whistle-blower whose account was suppressed by the official investigative panel that Clinton convened to review the episode, the Accountability Review Board (ARB). Thompson’s lawyer, Joseph diGenova, a former U.S. attorney, has further alleged that his client has been subjected to threats and intimidation by as-yet-unnamed superiors at State, in advance of his cooperation with Congress.

Sources close to the congressional investigation who have been briefed on what Thompson will testify tell Fox News the veteran counterterrorism official concluded on Sept. 11 that Clinton and Kennedy tried to cut the counterterrorism bureau out of the loop as they and other Obama administration officials weighed how to respond to — and characterize — the Benghazi attacks.

“You should have seen what (Clinton) tried to do to us that night,” the second official in State’s counterterrorism bureau told colleagues back in October. Those comments would appear to be corroborated by Thompson’s forthcoming testimony.

State Department spokeswoman Jen Psaki called the counterterrorism officials’ allegation “100 percent false.” A spokesman for Clinton said tersely that the charge is not true.

Keeping the counterterrorism bureau in the loop would have required dealing with practical recommendations involving military action and would have led to realistic assessments of the attack.

By cutting counteterror out of the loop early in the game, Hillary Clinton showed that the coverup which attributed the attack to a protest over a video gone wrong wasn’t belated, it began right out of the gate. Clinton and top State Department officials chose to minimize what was going on and to abandon their people on the ground right from the start.

There was no reason to cut the counterterrorism bureau out of the loop unless Hillary Clinton never wanted to address this as a terrorist attack or to save the Americans in Benghazi right from the outset.